What is the range of straightness measurement in straightness measurement optics?

• A. ¬¨¬®¬¨¬±2.5 mm
• B. ¬¨¬®¬¨¬±5 mm
• C. ¬¨¬®¬¨¬±10 mm
• D. ¬¨¬®¬¨¬±20 mm